Optimization of RFCC Process Considering Particle Deposition Model

Formation of particle deposit in the reactor cyclone of the commercial residue fluidized catalytic cracking (RFCC) process is one of the major problems causing serious catalyst carryover into the fractionators and process shutdown. This problem has been considered as an unavoidable issue in sustainable operations and required an accurate forecasting model. The particle deposition model in the cyclone dipleg of RFCC process is developed considering both of mathematical particle deposit factors and actual operating data. The model for particle deposition was researched in the viewpoint of transport phenomenon of particle. Verification of the model is conducted with actual plant data using parameter estimation method. Optimization model of RFCC process is developed by combining particle deposition model and cracking reaction model to find optimal operating conditions. The optimal operating conditions are found by selection of reaction temperature, catalyst/oil ratio and feed rate, to minimize particle deposit thickness. As a result, the operating cycle time is increased from 31 to 47 months (52%) by the decreasing particle deposition rate and the productivity of gasoline is increased at about 46% by increasing RFCC operation period.